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April 3,2001 <br /> Job Number: LGO1-074 <br /> Page 7 <br /> r. was drilled. <br /> Two percolation tests were conducted at the site. One test was conducted in the primary <br /> leach field and the other in the secondary leach field. The percolation test borings were drilled <br /> utilizing a 4-inch diameter hand auger. The casing used for the test was 2-inch diameter PVC <br /> pipe with an open end on the top and bottom. Perforations were made on approximately the last <br /> 12 inches of the casing. Two (2) inches of"pea gravel"was placed in the bottom of the hole,the <br /> casing was installed, and one (1) foot of"pea gravel"was backfilled in the annular space. The <br /> percolation test borings was pre-soaked 24-hours prior to the test. <br /> A one(1)hour percolation test was conducted for each location. The reserve leach field <br /> (P-1)was tested on March 13, the primary field (P-2) was tested on March 27, 2001 in <br /> accordance with the requirements of San Joaquin County Environmental Health Division. The <br /> _ percolation tests were observed by Mr. Ted Norgard (March 13, 2001) and Mr. Johnny Yoakum <br /> (March 27, 2001) of the San Joaquin County Environmental Health Division. The location of the <br /> tests are shown on the Site Plan (Plate 1). A satisfactory percolation rate of 1.3 minutes per inch <br /> was achieved for P-1 (reserve leach field) and 2.8 minutes per inch was achieved for P-2 <br /> (primary leach field). <br /> The soils within the primary and reserve leach fields were found to be variable in <br /> composition. The percolation rates reflect the most permeable layers encountered between the <br /> surface and 10 feet in depth. The surface soils were found to be composed of silty and clayey <br /> soils which will not percolate as fast as the soils tested at 6.5 feet in depth. The use of seepage <br /> pits will be necessary for effluent disposal. Since the septic system is expected to dispose of <br /> relatively high quantities of effluent, extra care should be employed during construction of the <br /> seepage pits to ensure that permeable soils are encountered. <br /> VII. NITRATE LOADING STUDY <br /> A build up of nitrates in ground water can cause a temporary blood disorder in infants <br /> called methemoglobinemia(blue baby syndrome). Serious and occasionally fatal poisonings of <br /> infants have occurred following the ingestion of water containing nitrate concentrations greater <br /> than 10 mg/l nitrate as N or 45 mg/1 nitrate as NO3. <br /> Because of the concern of nitrate leaching into ground water, a nitrate loading analysis <br /> was required by the County to estimate the average nitrate concentration of percolating water for <br /> the subject parcel. If a site is contributing excess nitrogen to ground water, ground water quality <br /> r ' CE;SOS <br /> Z <br /> O ` <br /> 7'fSOGā™¦ <br /> r <br />